ENDOTHELIN-1-21 PLASMA-LEVELS IN FETUSES AT 18-24 WEEKS OF GESTATION

This study aimed to establish normal endothelin (ET) ranges in non mal formed appropriate for gestational age fetuses of 18-24 weeks gestatio n and to investigate a possible correlation between maternal and fetal ET plasma levels. Twenty ''mother-fetus'' pairs were included in the study. The determination of ET 1-21 was performed by radioimmunoassay using 1 ml of fetal blood obtained by cordocentesis - indicated for va rious reasons - and in 2 ml of maternal venous blood. The statistical analysis involved the Wilcoxon test for pair differences and the Spear man rank correlation coefficient. Fetal and maternal ET 1-21 levels we re respectively 11.39 +/- 2.22 pmol/L and 6.44 +/- 1.00 pmol/L. Fetal levels were significantly higher (p < 0.01) thus excluding passive ET transfer through the placenta, while no correlation between maternal a nd fetal levels was found. It is speculated that high fetal ET 1-21 le vels result from increased ET production, which possess cell prolifera tive properties and/or decreased ET removal from the fetal circulation because of hypofunctioning lungs and kidneys. It can be assumed that the increased amounts of fetal ETs contribute to normal growth and dev elopment directly as well as by regulating vascular tonus and local bl ood flow.